Julio and Septiembre are two teenage sisters who live in their own world. Septiembre is dominant and reckless, sometimes cruel, while Julio is meek and fearful, introverted, naive and accommodating. They are like two peas in a pod: the close bond that unites them, their devotion, the strange tests they undergo to prove their loyalty and the way they complete each other make it impossible to know where one begins and the other ends.

Julio's fragility has caught the attention of the bad girls at school, triggering a macabre event –barely hinted at– that will force them to move with their mother, a children's literature writer, from Oxford to a ramshackle house owned by their paternal aunt, located in the middle of nowhere, where an oppressive and unsettling atmosphere reigns.

Daisy Johnson, a great stylist and aware that what is not said or described can be as disturbing as what is revealed, once again masterfully and elegantly doses out the revelations and ellipses in an absorbing suspense novel halfway between the gothic genre and a mythological fable, in which she explores the relationships between sisters and warns us of the dangers of loving too much.